Human skin is a composite material of the epidermis and the dermis. The topmost part of the epidermis is the stratum corneum. This layer is the stiffest layer of the skin, as well as the one most affected by the surrounding environment. Below the stratum comeum is the internal portion of the epidermis. Below the epidermis, the topmost layer of the dermis is the papillary dermis, which is made of relatively loose connective tissues that define the micro-relief of the skin. The reticular dermis, disposed beneath the papillary dermis, is tight, connective tissue that is spatially organized. The reticular dermis is also associated with coarse wrinkles. At the bottom of the dermis lies the subcutaneous layer.
The principal functions of the skin include protection, excretion, secretion, absorption, thermoregulation, pigmentogenesis, accumulation, sensory perception, and regulation of immunological processes. These functions are detrimentally affected by, for example, dryness, yeast, and structural changes in the skin, such as due to aging and excessive sun exposure.
Various pharmaceuticals have been used for the treatment or prevention of skin conditions, including skin cleansing compositions. Some of these compositions are discussed below.
Canadian Patent No. 1,174,976 discloses a germ-killing skin medication including two gels to be applied and mixed in situ, the first gel having sodium chlorite in an aqueous form and the second gel having lactic acid in an aqueous gel.
Great Britain Application No. 2,076,286 A discloses a dermatological composition of an oil medium dispersed in an aqueous medium that contains hydrogen peroxide, a buffer to maintain the composition below a pH of 7, and a starch gelled in situ. The buffer may include lactic, citric, tartaric, maleic, or hydroxysuccinic acids with an acid salt.
Great Britain Application No. 2,189,394 A discloses a concentrate that can be mixed with hydrogen peroxide to become an effective disinfectant for water, foodstuff, animal feeds, equipment, packages, and the like. The concentrate includes an inorganic acid with a pH less than 1.6, a silver compound or colloidal silver, an organic acid stabilizer such as tartaric, lactic, salicylic, or citric acid, and optionally gelatin.
European Patent Application No. 0,191,214 A2 discloses a cosmetic liquid cleanser for treating blemished, scarred, or inflamed skin having boric acid or borax, ammonium hydroxide, a peroxide, and optionally salicylic acid.
European Patent No. 0,250,539 B1 discloses a stabilized aqueous hydrogen peroxide composition having 0.1 to 4 weight percent hydrogen peroxide and 0.5 to 5 weight percent .beta.-crystals of one or more lipids selected from monoglycerides of fatty acids, ascorbic acid, phosphate or lactic acid esters of fatty acids and monoglycerol ethers, said fatty acids and ether chains being saturated and having 12 to 18 carbons.
European Patent No. 0,425,507 B1 discloses compositions for treating abnormal or damaged conditions of the epithelium including skin, which include 0.01 to 12 weight percent of an activated protein containing at least 0.5 weight percent cysteine, 0.1 to 15 weight percent of a reducing agent to reduce cystine to cysteine, and 81.0 to 99.889 weight percent water, acids, bases, buffering agents, emulsifying agents, thickeners, solvents, preservatives, coloring agents, and perfuming agents. The reducing agent may be a salt of a thioglycolic acid. In a preferred embodiment, the composition also includes an oxidizing agent, such as hydrogen peroxide.
U.S. Pat. No. 3,297,456 discloses cleaning and polishing compositions, particularly for floor waxing, having lactic acid, methanol, hydrogen peroxide, and aqua ammonia in a particular ratio.
U.S. Pat. Nos. 4,015,058 and 4,015,059 disclose stable peroxy-containing concentrates useful for the production of microbicidal agents consisting essentially of an aqueous mixture of 0.5 to 20 weight percent peracetic or perpropionic acid or their precursors, 25 to 40 weight percent hydrogen peroxide, and optionally up to 5 weight percent anionic surface-active compounds of the sulfonate and sulfate type. Also disclosed are compositions that further include 0.25 to 10 weight percent organic phosphonic acid capable of sequestering bivalent metal cations and their water-soluble acid salts.
U.S. Pat. No. 4,203,765 discloses an aqueous acidic etch-bleach solution of hydrogen peroxide, iron ions, and inorganic anions that form a silver salt, such that in the dissolved state the solution contains citric acid and a polymer of alkylene oxide units for stabilization of the hydrogen peroxide.
U.S. Pat. No. 4,438,102 discloses compositions containing gelatin, hydrogen peroxide, ammonium hydroxide, thioglycolic acid, and a lower alkanol to promote the growth of dermal and epidermal tissue.
U.S. Pat. No. 4,534,945 discloses an aqueous 25 to 35 weight percent solution of hydrogen peroxide stabilized against decomposition with up to 1.4 mg/L tin, which is maintained in solution by particular amounts of phosphate in the form of phosphonic acid and hydroxycarboxylic acid.
U.S. Pat. No. 4,557,935 discloses a germicidal composition of hydrophilic lipid crystals of 1-monolaurin, and preferably 1-monomyristin, and hydrogen peroxide, whereby the former stabilize the latter. Optionally, the compositions further contain salicylic acid.
U.S. Pat. No. 4,900,721 discloses liquid, aqueous disinfectants based on alcohol and hydrogen peroxide that contain one or more C.sub.2-8 alcohols, hydrogen peroxide or a hydrogen peroxide forming compound, one or more carboxylic acids, one or more microbicidally active nitrogen-containing organic compounds, one or more microbicidally active phenolic compounds for disinfection of the skin and mucous membrane.
U.S. Pat. No. 5,139,788 discloses an antimicrobial surface sanitizing composition having a diluent and antimicrobial agent of an antimicrobially effective amount of alpha-hydroxyacid substituted mono- or di-carboxylic acid and an antimicrobially effective amount of hydrogen peroxide, such that the composition leaves a non-contaminating residue after contact with surfaces to be disinfected.
U.S. Pat. No. 5,693,318 discloses phosphate esters for the improvement of water solubility of salicylic acid and peroxide compounds in an aqueous cleanser.
Despite these references, a stable composition of hydrogen peroxide, a hydroxy acid, and an antimicrobial agent has not been prepared and used for cleansing skin and managing skin conditions. Thus, there is still a need for improved pharmaceutical compositions and methods capable of cleansing the skin to facilitate the prevention, treatment, and management of skin conditions, such as folliculitis, seborrheic dermatitis, psoriasis, rosacea, perioral dermatitis, acne, impetigo and other inflammatory skin conditions, and the like. The present invention advantageously provides pharmaceutical compositions and methods for cleansing skin to facilitate the prevention, treatment, and management of one or more skin conditions.